MFC rev. 1.273, submitted by peter:
MFC rev. 1.273, submitted by peter:

Change kn_hook value from cdev to struct tty to avoid dereferencing freed
cdev.
In ttygone(), wake up select(), sigio and kevent() users in addition
to the queue sleepers.
Return EV_EOF from kevent filters if TS_GONE is set.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase